<?php
namespace Yipresser\AdminOptimizer\Modules;

use Yipresser\AdminOptimizer\Base_Module;

// Exit if accessed directly.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Ads_Robots_Txt class
 */
class Ads_Robots_Txt extends Base_Module {
	const OPTION_NAME = 'adminoptim_ads_robots_txt';
	const MODULE_ID   = 'ads_robots_txt';
	const MODULE_SLUG = 'ads-robots-txt';

	const MENU_SLUG = 'adminoptimizer-adstxt';

	const MODULE_URL = ADMINOPTIMIZER_MODULES_URI . 'ads-robots-txt/';

	/** @var string Option flag set once the one-time un-escaping migration below has run. */
	const MIGRATED_OPTION = 'adminoptim_ads_robots_txt_decoded_v1';

	/**
	 * Start the engine running
	 *
	 * @return void
	 */
	protected function init(): void {
		$this->settings = new Ads_Robots_Txt_Settings( $this->options );
		add_action( 'init', [ $this, 'display_entries' ] );
		add_filter( 'robots_txt', [ $this, 'output_robots_txt' ], 999999, 1 );
		add_action( 'admin_init', [ $this, 'maybe_migrate_escaped_content' ] );
	}

	/**
	 * Display ads.txt and app-ads.txt content
	 *
	 * @return void
	 */
	public function display_entries() {
		$path    = $this->resolve_request_path();
		$content = null === $path ? null : $this->get_virtual_file_content( $path );

		if ( null === $content ) {
			return;
		}

		header( 'Content-Type: text/plain; charset=utf-8' );
		header( 'X-Content-Type-Options: nosniff' );
		echo $content; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- stored plain-text file content, served verbatim as a text file, not HTML.
		die();
	}

	/**
	 * Resolve the current request's path, ignoring any query string, so
	 * `/ads.txt?v=2` still matches the virtual file.
	 *
	 * @return string|null
	 */
	private function resolve_request_path(): ?string {
		if ( empty( $_SERVER['REQUEST_URI'] ) ) {
			return null;
		}

		$request = esc_url_raw( wp_unslash( $_SERVER['REQUEST_URI'] ) );
		$path    = wp_parse_url( $request, PHP_URL_PATH );

		return is_string( $path ) ? $path : null;
	}

	/**
	 * The virtual ads.txt / app-ads.txt content for a given request path, or
	 * null when the path doesn't match a configured virtual file.
	 *
	 * @param string $path Request path (no query string).
	 * @return string|null
	 */
	public function get_virtual_file_content( string $path ): ?string {
		if ( '/ads.txt' === $path && ! empty( $this->options['adstxt_content'] ) ) {
			return (string) $this->options['adstxt_content'];
		}

		if ( '/app-ads.txt' === $path && ! empty( $this->options['app_adstxt_content'] ) ) {
			return (string) $this->options['app_adstxt_content'];
		}

		return null;
	}

	/**
	 * Output robots.txt content
	 *
	 * @param string $output robots.txt content.
	 * @return string robots.txt content
	 */
	public function output_robots_txt( $output ) {
		if ( ! empty( $this->options['robotstxt_content'] ) ) {
			$output = (string) $this->options['robotstxt_content'];
		}
		return $output;
	}

	/**
	 * One-time migration: values saved before the double-escaping fix are
	 * stored HTML-entity-encoded. Decode them once, guarded by a stored
	 * flag so repeat admin_init hits are a cheap no-op.
	 *
	 * @return void
	 */
	public function maybe_migrate_escaped_content(): void {
		if ( get_option( self::MIGRATED_OPTION ) ) {
			return;
		}

		$options = get_option( self::OPTION_NAME, [] );
		$changed = false;

		foreach ( [ 'robotstxt_content', 'adstxt_content', 'app_adstxt_content' ] as $key ) {
			if ( ! empty( $options[ $key ] ) && is_string( $options[ $key ] ) ) {
				$options[ $key ] = wp_specialchars_decode( $options[ $key ], ENT_QUOTES );
				$changed         = true;
			}
		}

		if ( $changed ) {
			update_option( self::OPTION_NAME, $options );
			$this->options = $options;
		}

		update_option( self::MIGRATED_OPTION, 1 );
	}
}